Caltrans geotechnical experts will conduct an investigation, and no estimate was given for when the highway would reopen, the spokeswoman said.

Motorists traveling to Idyllwild were advised to use State Route 74 through Hemet. The unincorporated community of Pine Cove can be accessed from Interstate 10, Kasinga said.

“Motorists can reach the Pine Cove area from I-10, however not Idyllwild,” Riverside County transportation officials said. “Motorists traveling to communities north of Pine Cove, such as Idyllwild, must use SR 74 through Hemet to SR 243 as a detour.”